Plasma cutting and welding are achieved through the use of a plasma torch. During plasma cutting, an inert gas is blown at high speed out of a nozzle of the plasma torch. At the same time an electrical arc is formed through the inert gas from the nozzle to the surface of a workpiece. The electrical arc turns some of the inert gas to plasma. The plasma jet is sufficiently hot to melt the workpiece. The plasma jet is also blowing fast enough to blow molten metal away from the cut in the workpiece. Plasma welding utilizes a similar concept, only the plasma jet does not penetrate as deeply into the workpiece.
Thermal working of a workpiece can also be accomplished using an oxy-fuel torch. An oxy-fuel torch uses fuel gases and oxygen to weld or cut a workpiece. During oxy-fuel welding, oxygen is used to increase the temperature of a flame emitted from the torch to allow localized melting of the workpiece. During oxy-fuel cutting, the torch is used to heat the metal to its kindling temperature. A stream of cutting oxygen is then trained on the workpiece to cut the workpiece.